Integrate test coverage in the CI

[ggonzalez94]

Report test coverage on every PR and on the main branch.

MUST:

• Show the coverage on the CI logs
• Upload to Codecov for easy visualization
• Ignore vendor files and mocks

SHOULD:

• Show the diff for every PR so we know if coverage is improving or decreasing

[suratkhan]

hey @ggonzalez94, can you assign me this task? I would like to work on this.